The phytonutrient sulforaphane (SF), which is naturally derived from glucoraphanin found in broccoli, is a potent antioxidant enzyme inducer. The immune system, comprised of both the innate and adaptive immune response, plays a key role in the pathogenesis of inflammation, which is a key underlying mechanism in many chronic diseases. The objective of the study was to investigate the immuno-inflammatory modulating effect of SF on stimulated human monocytes and peripheral blood mononuclear cells (PBMCs). SF time (8 and 24 hrs) and dose (0 – 20 uM) dependently attenuated TLR2 and TLR4 expression by flow cytometry, decreased MYD88 and NFKB activity, and attenuated the secretion of several inflammatory chemokines and cytokines, including MCP-1, IL-1beta, IL-6, IL-12, TNFalpha, and IFNgamma, achieving apparent IC50 concentrations of 0.5 – 10 uM. Gene expression analyses of 184 key pro/anti-inflammatory genes provide further insights into the effect of SF on underlying mechanisms of immuno-inflammatory modulation. In summary, SF modulates in vitro inflammatory activation in stimulated human monocytes and PBMCs within the range of human plasma SF concentrations achieved through consumption of high glucoraphanin broccoli.